Necticut



Sept. 27,1927.

D. L. SUMMEY ART OF' FURNACE LINING Filed Oct. l, 925

IMI-Mr li :Il Il lllllllllllll Illnllillllllill Svwenoz f; QMMQ 4 @WNYPatented Sept. 27,1927.

UNITED STATES PA'raN'r'orrlcl-z.

DAVID L. SUMMEY, OF WATERBUBY, CONNECTICUT, ASSIGNOB TO BCOVILL MANU-FACTURING COMPANY, OF WATERBURY, CONNECTICUT, A CORPORATION F CON-NECTICUT.

ABT OF FURNACE LINING.

Application nled October 1, 1826. Serial Ha. 138,858.

This ,invention relates to the art of furnace lining.

.In a known type of induction furnace which may be cited as an 'example,anI ino terior channel or passage/usually roughl V-shaped, communicatesat its two en s with the hearth of the furnace. This channel :rfceiv'esa portion of the molten bath which acts as the secondary of the transl0former'and the molten metal is circulated through the channel, therebyestablishing. a circulation of vthe bath for thev eectivc transmissionof heat to the charge.. Such a furnace is shown in U. S. patent to Jamesl R. Wyatt, No. 1,201,671.

The channel referred to, because of the hi h temperatures involved, isbounded by refractory material. According to known practice, the channelis formed by'tamping refractory material around a tem let or pattern ofthe shape of the desired c annel, allowing the refractory material toset, and removing or destroying the templet by means of heat. Ifexpansion of the templet, under 25, the application of heat, is notprevented, the

surface of the refractory lining is liable to jbe cracked or otherwiseinjured by such expansion.

It is an objectof the present invention to provide a method of and meansformanufacturing furnace linings effectively and economically, avoidininjury to the lining by expansion of the orm.

With this general object, and others, in

view, the invention consists in the features,

combinations, details of construction and arrangements of parts whichwill first be described in connection with the accompanyin drawing andthen more particularly w pointed out.

. the furnace.

lustrated as an example comprises a furnace body 11 formed of irebr'ickor other suitable material and enslosedin a metal casing 12. Within theboci.7 is a furnace lining 13 of suitable rfrac v*y material. Thefurnace has a pouhng aio-ut 14 and a charging door 15 communicatingwitb'tlc" hearth 16.a Communicatingwith the lower'part of the hearth arethe two ends of'a substantially V-shaped channel indicated` at 17. Thischannel is bounded by the refractory lining 13, the outer definingsurfaces mergin into the straight walls of the hearth an the innersurfaces merging into aaounded hearth bottom,.as shown in Fig. 1l

Surrounding the upper ends of the chan- /nel is the core 18 of atransformer with a primary coil suitably wound and connected, the innerleg of the core and the primary coil being encased in a shell 19. Whenthe furnace is in operation the molten metal in the channel acts as thetransformer, secondary.

The lower part of the furnace lining, that is, the part which bounds thechannel, is formed by tampin refractory material about a tem let anremoving the templet after the re raetory material has properly set.While various refractory materials having various consistencies may beused, a dampened granular material having a consistency somewhat likedamp sand has been' found suitable.

According to the present invention, there is provided a templet or formhaving substantially the shape of the channelto be formed, destructibleby heat, and capacitated to be rendered collapsible in the initialheating period. This may be accomplishes?, for example, by providing thetemplet ith a relatively weak or low heat-resisting portion following agiven line around the periphery of the templet and, in effect,connecting two halves separated by a plane longitudinal of The templetmay conveniently be constructed of wood as such a templet is easy tobuild and easy to burn out. In such cases, the weak portion may be arelaw tively thin wall so arranged that when the templet is heated up tothe point of combilstion, the material of the thin wall is consumedfirst, i. e., during a preliminary combustion period. This destruction othe dividing wall separates the templet into two ole lll

pants collapsible. one toward the other. thereby to take up orcompensate for any tendene-y of the Wood to expand during the maincombustion period.

While the templet may vary in construetion, in the embodiment hereillustrated as an example, it comprises a V-shaped wooden frame or form20, the legs of the V being connected at the top by two spaced straps 21which define a groove at the bottom of the furnace pool. The outer edgesol the V merge into straight lines corresponding to the sides of thehearth. as appears in Fig. 1. The inner edges of tbe V merge into acurve which is continued by the bottom edges of the straps 21, thiscurve corresponding to the rounded portion of the furnace bottom at thebottom of the hearth.

The whole frame is somewhat the shape of' bore is so dimensioned that atthe longitudinal lines where the bore most Closely approaches atangential relation with the faces 23, 24, of the form, there is left arelatively thin double wall Q5, strong enough to hold the templet rigidunder tamping pressure but thin enough to burn through easily. This Wallruns around the V, including the straight extensions, in a line, orrather a strip, located .substantially midway of the end edges 26, 9.7of the form and thus, in effect, connects tuo form halves separated by alongitudinal plane.

ln the embodiment illustrated, the bore 22 serves also as a conduit fora resistor strip or wire 28 which is threaded through the bdr'e. and hasits ends extending outwardly aty the top il) for connection in a.snitable circuit.

At opposite sides ot' bore Q2 are other channels or bores 29. 3l), forthe passage of an air or oxygen blast to aid combustion.

In use, the templet is suitably positioned and the refractory materialis taniped about, the same totorm the furnace lining. During thistamping the. form is rigid and ivithstands tamping pressure so as toconstitute a proper pattern for the. channel desired. After a propersetting period. the resistor strip 28 is connected in circuit and theheat set up therein heats the. wooden torm to the oint of combustion.Owing to the fact that the double Wall is relatively thin and Weak andnear the source of heat, it burns through during the initial stages ofcombustion, This. in effect, separates the form into two longitudinalparallel parts collapsible one toward the other. This separation takesplace before the form as a whole heats np sutiiciently to exert anysubstantial expanding pressure on the furnace lining. As a result, thetendency to expand is taken up by the collapse or inward movement of theseparated .form parts and injury to the lining is avoided. Bv continuedcombustion, which, may be aided by an air blast, the form is destroyedand the furnace Channel made ready for use.

that claimed is:

l. A tel'nplet for the purpose described, providing a pattern havingsubstantially the shape of theahannel to be formed and eapacitated to bedestroyed by the applica` tion of heat, and having a portion runninglongitudinally around the templet between tluend edges and eapacitatedto be destroyed by heat relatively rapidly with respect to the patternas a whole, whereby upon application of heat the templet is relativelyearly divided int-o two parts movable one toward the other.

2. A tem let for the purpose described, composed o wood and providing apattern having substantially the shape of the channel to be tormed, andhaving a portion extending around the body of the templet between theedges thereof and arranged, upon Combustion, to burn out relativelyrapidly with respect to the combustion of the form al large, thereby todivide the tem let into two parts movable one toward t e other prior tothe major combustion.

il. A templet for the purpose described, composed ot' wood and providina pattern having substantially the shape the chan nel to be formed. andhaving, substantially midway ot its end edges, relatively thin portionsin the inner and outer walls, whereby upon `combustion such thinportions burn out relatively rapidly with respect to the combustion ofthe attern at large, thereby to divide the temp ct into two parts niet"able one toward the other prior to the ma combustion.

l. A templet for the purpose describri, composed ot' wood and providin apatte"-` having sul'istantially the Shape 01% the chafa nel to heformed, and having substantially' midway ol its end edges a bore runningaround the body of the templet and forming relatively thin portionsinthe inner and outer walls, whereby upon combustion Such thin portionsburn out relatively rapidly with respect t0 the combustion of the pat.-tern at large. thereby to divide the tem let into two parts movable onetoward the ot er prior to the major Combustion.

5. A teni let for the purpose described, composed o Wood and providing apattern having substantially the shape. of the chan nel to be formed,and having substantially midway of its end edges a bore running aroundthe body of the templet and forming relatively thin portions in theinner and outer wells, whereby upon combustion such thin portions willburn ont relatively rapid ly with respect to the combustion of thepattern at large'.Y therebyto divide the templet into two parts movableone toward the other, and supplemental bores on either side of saidfirst named bore.

6. The method of making the refractory structure of an electric furnacehaving an interior channel, which comprises forming 'a pattern havingthe shape of the channel to be formed, tamping refractory material aboutsaid pattern. causing a portion of Said pattern, in a dividingstrip-runningr longitudinally around the body thereof, to be destroyed,whereby the pattern is divided into two portions movable one toward theother, and destroying the remainder of the pattern.

7. The method of making the refractory Structure of an electric furnacehaving an interior channel, which comprises forming a pattern haring theshape of the channel to he formed and having a bore running lonitndinally around the pattern t0 form re atively thin side wall portionssubstantially midway of the ends. tamping refractory ma.- terial aboutsaid pattern, applying lieat to the pattern to burn through said Wallortions, wherebythe pattern is dividedhnto two portions movable onetoward the other, and further Supplying heat t0- burnthe remainder ofthe pattern.

In testimony whereof, I have hereunto set my hand.

DAVID L. sUMM'EY.

